Electric clock



l ELECTRIC CLOCK Filed AAug. 22, 1931 Patented Nov. 5, 1935 UNITEDSTATES PATENT OFFICE ELECTRIC CLOCK ceased, assigner to N. Y.

Application August 22,

6 Claims.

My invention is an electric clock of the type run from a regulated A. C.current. By regulated current, I mean a current whose frequencyisregulated at the power house sothat the average 6 cycles per second ofthe current is exactly some predetermined number, usually 60.

One of the objects of my invention is a clock of this type which willbridge over a period of no current and so keep up the motion of theclock hands during a short period of interruption to the current`supply. Another object of my invention is t-he provision of a recoilescapement in aclock of this type to the end that the clock will startitself as soon as power is supplied to it, and not have to be started byoutside means as is the case of clocks with a detached escapement (forexample, a lever escapement) heretofore used.

A further object of my invention is the elimination of the synchronousmotor used in clocks of this type and the substitution therefore of avibrating reed and connections thereto to keep the clock movement insynchronism with the A. C. current.

A further object of my invention is the provision oi' a frequencyreducer to step down the frequency of the cmrent to a sub-multiple valueand then by means of a vibrating member in step with said reducedcurrent to bring a clock movement in step therewith. The frequencyreducing means 30 may be electrical, mechanical or a combination ofboth, as is most convenient for the particular conditions to be met.

'Ihe above and other objects of my invention will be described inthefollwing specification and set forth in the claims.

Before giving a detailed description of the mechanism of my invention, Iwill first give a short description of the principles on which it isbased. In the preferred form of my invention, I employ a continuouslyrunning clock movement, the power to run which may be obtained from thesource of regulated current. Alternatively, the clock may be wound byhand or by.

any suitable battery actuated wind. I'he clock escapement is of therecoil type. since as will be afterwards pointed out, I am not concernedthat it keep exact time. 'I'he balance wheel of the ciocor the pendulum,as the case may be, is more orless governed as to its time of vibrationby a spring or its equivalent. 'I'he other end of this'spring isarranged to be vibrated periodically by an element actuated in step withthe current and preferably at some frequency which is a submultiple ofthe current frequency. for instance,

1931, Serial No. 558,773

one-half or one-third. I have discovered that even if the frequency atwhich the end of the spring is vibrated is a multiple of the naturalfrequency of the balance and its spring, the balance will be forced intostep. 5 To take a specific case: Assume that the balance of the clockmakes three oscillations per second and that the current frequency is60. Then there is a factor of 20 between the balance and the current. Afactor of 5 may be taken care of between 10 the current and the membervibrated by said current and a factor of 4 between the vibrating memberand the balance. That is, an electromagnet, excited by the 60 cyclecurrent, vibrates a. reed at a frequency of l2 and the reed' vibrates 15the end of the balance spring at a frequency of l2 (four times thefrequency of the balance system) and thu's keeps the balance, whosefrequency is three, in step, both with the reed and the current. Bymeans of this system of frequency reduction. 20 I do not need asynchronous motor and its associated system of gear reduction, and amfree also from the concomitant lubrication troubles.

With the help of these preliminary remarks. my invention may be bestunderstood by reference 25 to the accompanying drawing of which:-Fig. lis a diagrammatic drawing of a clock embodying my herein describedinvention and Fig. 2 is an alternative circuit which may be usedtherewith. In Fig. 1. for the sake of clearness, the balance 30 andescapement are shown on a larger scale than the remainder of the clock.

In Fig. l, Ill and II are line conductors which supply regulatedcurrent. Ihese are connected by wires I2 and I3 to a winding I4 on anelectro- 35 magnet I6, having curved poles IB and Il which define analte ating magnetic eld in which vibrates a reed Il, held by a block I9in the framework. 'Ihe reed I8 supports a block 20 in whichis a timingscrew 2| to adjust the frequency of 40 the reed. The reed I8 alsosupports an arm 22 to which is secured one end of a balance spring 23whose other end is fastened to a balance stai 24. A balance 25 is on thestall' 24 and is provided with four timing screws of which two, 26 45and 21, are shown. The staff 24 is also provided with two arms 28 and 29projecting therefrom and alternately engaged by the pins 30 in a crownwheel 3i mounted on a staff 32. The arms 28 and 29 with the pins 30 willbe recognized as 50 forming the well-known verge escapement.

Power is supplied to the wheel 3l in the usual manner by a pinion 33 onthe stai 32 engaging a wheel 3l on a stati' I5 having a pinion 36 drivenby awheel Il on a stad I8 which carries a pinion 55 89 driven bythecenter wheel 4l on a stad Il revolving once an hour. The stall' Ilcarries a minute hand 48 and a cannon pinion 42 which drives anintermediate wheel ltturning on a stud 45. A pinion 44 on the wheel 4Iturns a wheel (not shown) to which is attached the hour hand l1.

Power is supplied to the center )wheel I by a s gear Il meshingtherewith; said gear is on a shaft I! to which is attached one end of amainspring IU mounted in a barrel is fastened the outside end o:the-spring se. said spring is wound to a certain tension, after whichthe clip starts tol slip in the barrel 52, thereby A preventing. furtherwinding of the spring. 'Ihe barrel $2 is provided withteeth 53 which aredriven by a worm 54 on a shaft l5 which carries anism is well known anddoes not require extend -of the clip El.

ed description. The magnet III is excited by a winding 62 connected bywires 63 and 64 to the line wires I0 and Il.

' From the preceding, the operation of my improved clock will be clear.The line current drives the disc 59 which, by the connecting gears,turns the barrel 52 and winds the spring 5E faster than the running ofthe clock will unwind the shaft 49. excess wind being taken care of bythe slip Driven by the. clock train. the verge escapement 4vibrates thebalance 25 at a rate approximately determined, by the spring 23. Thereed Il isvibrated by the regulated current and onaccount of itsconnection-with the end of the balance spring 2l holds the balance 25 instep. Ihus theV hands of -the clock will revolve at a rate determined bythe frequency of the regulated current.

In the event the current is interrupted, the

stored power of the spring-SII will keep the clock going until saidspring is-run down. When the current is again resumed. the reed Il willpick up its vibration and the balance will be held in step againLwiththe error of the .clock that accumulated during a period of no current.However. the periods of no current in the ordinary commercial system arequite rare and of short duration so the time kept by my herein describedclock will be practically that determined by the frequency of theregulated current.

In Fig'. 2, I have shown an electrical method of reducing the frequencyof the regulated current by means of a multivibrator circuit well-knownin the radio art. This device, with an input of say 60 cycles, will givean output of some submultiple of 60, say 6 cycles per second. 'I'hesubmultiple frequency is held rigorously with the main frequency. Thecircuits and description for the vmultivibrator may be found in RadioEngineer-' ing Principles, Lauer and Brown, second edition, page 20'8 etseq. McGraw-Hill Book Co. 1928: also in Reception des Signaux Horairespage 68 et seq.. published for the Bureau of Longitudes Paris byGauthier-Villars et Cle., Quai desv Grands-Augustine 55, in 1924. In thegure, a multivibrator Il is connected to the line wires Il and Il.Conductors 65 and 68 connect the multivibrators 61 with the winding Ilof'the magnet Il. In the event of using the circuit shown in Fig. 2, themultivibrator `may reduce the frequency 10 times toafrequencyofathereedilmayreducetimes tz, the inside of which is Yfrictionally engaged by a spring clip Il to which'V l departing from thespirit .of

of the balance 25.

It wilLbe obvious that the reduction factor may be distributed 'in anydesired manner between the agencies of the multivibrator, the reed. andthe l5 balance. It is necessary only that their combined product be thefrequency of the regulated current. This property gives a ilexibility tomeet varied requirements which my invention may have tn meet.

The reed Il has a large restoring force compared to the spring 23. sothat the force of the latter may be swamped in .the force of the former.

' It is also preferable that the reed I8 be polarized which may be doneboth by` making it a perl5 manentmagnet or providing a permanent mag- 1netic ileld to polarize it.

-In the following claims, I have used the term "submultiple frequency"by which I mean a frequency which is that of the fundamental divided 20Vby an integer other than one:i For example, 12 is a submultiple of 60since it equals 60 divided by 5.

I consider the use of a vibrating reed as a substitute for a synchronousmotor in clocks of this kind of great advantage. it is self-starting andhas 25 no lubrication troubles.

Many changes and modifications may be made in the' precise structureherein shown without my invention since I claim 1. In an electric clock,the combination of a source of alternating current, an oscillatingmember, a spring connected to said`-member, a reed vibrating instep withsaid current. and a connection between said reed and said spring whereby said oscillating member is kept in step withsaid current. l

y 2. In an electric clock the combination of a source of alternatingcurrent, an oscillating member, a spring connected to said member.- areedsoJ vibrating in step with said current at submultiple frequency anda connection between said reed and said spring whereby said oscillatingmember -iskeptinstepwithsaidcurrent.

8. In an velectric clock the combination of a source of alternatingcurrent, and oscillating member, a recoil'escapement to drive said'oscillating member. a spring connected to said member a' reed vibratingin step with said current at submultiple frequency and a connectionbetween said reed and said spring whereby said oscillating member iskept in step with said current.

4. In an-electric clock, the combination of a source of alternatingcurrent, a reed vibrated by said current, at a certain frequency, abalance 5 5 y having a frequency a submultiple of that of said reedand'means whereby said reed forces saidl balance into step with saidcurrent.

5. In an electric clock the combination of a `sc urce of alternatingcurrent having a certain frequency. an electromagnet connected tosaidcurrent having an amature vibrating at a submultiple frequency, abalance having a submultiple frequency to that of said armature andconnections between said armature and said balance 4 to hold saidbalance in step with said current. i 6. In an electric clock thecombination of a source of alternating current, a reed vibrated by saidcurrent at a submultiple frequency of said lcurrent, a balance having asublnultiple fre- 'I0 quency to said reed and a spring having one endattached to said reed and the other end attached"- to said balance.

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